Omicron-amino-p-cresol-carboxylic-acid and process of making same



Patented Mar. 1, 1932 rates PATENT OFFICE LEOPOLD LASKA AND OSKAR HALLER, OF OFFENBACH-ON-THE-MAIN, GERMANY, AS- SIG-NOBS TO GENERAL ANILINE WORKS, INC., OF NEW YORK, N. Y., A CORPORA- TION OF DELAW'ARE O-AMINOP-CRESOL-GAEBOXYLIC-ACID AND PROCESS OF MAKING SAME No Drawing. Application filed January 16, 1931, Serial No. 509,270, and. in Germany January 23, 1930.

Our present invention relates to oaminop-cresol-carboxyhc acld and to a process of making same.

The process of manufacture in accordance with this invention is by heating withcarbonic acid at super-atmospher c pressure an boxylic acid of the formula:

It is avaluable intermediate for the production of dyestuifs. I

In order to further illustrate our invention, the following examples are given, the parts being by weight and all temperatures in centigrade degrees. We wish it, however, to be understood that we are not limited to the particular products nor reaction conditions mentioned therein.

Example 1 1230 parts of 1-methyl-2-amino-l-hydroxybenzene are dissolved in 116 parts of caustic soda of 96% and 5000 parts of water in an autoclave provided with a stirrer and the water is distilled off, finally in vacuo, until the mass becomes entirely dry. Into the cold reaction mass carbonic acid is introduced until a pressure of 10 atmospheres and the whole is heated to 140 for 10 hours. The cold mass is dissolved in water. From the filtered solution the 1-methyl-2-amino-4-hydroXy-benzene-carboxylic acid is precipitated by means of hydrochloric acid. For further purification it is dissolved in sodium carbonate solution and again precipitated therefrom with an acid. When recrystallized from alcohol it melts at 164. The alcoholicsolution of t 11S acid yields an intense sherry-red coloration after the addition of a dilute solution of ferric chloride.

Ewample 2 1V hen in Example 1 the 416 parts of caustic soda are replaced by 560 parts of caustic potash and the process is otherwise carried on in the same way, a carboXylic acidis obtained which shows the same properties as the product of Example 1.

The temperature used may vary between 130 and 150, the pressure between 10 and atmospheres.

We claim:

1. A process for the manufacture of 1- methyl-2-amino-t-hydroxy-benzene-carboxylic acid which comprises heating to 130150 withcarbonic acid under a pressure of 1050 atmospheres an alkali metal salt of l-methyl- Q-amino-l-hydroxy benzene.

2. As a new compound the 'l-methyl-Q- amino 4 hydroXy-benzene-carboXylic acid corresponding probably to the formula:

which compound melts when recrystallized from alcohol at 164 and shows when mixed with ferric chloride in an alcoholic solution an intense sherry-red coloration.

In testimony whereof we affix our signatures.

LEOPOLD LASKA. OSKAR HALLER. 

